基于热中子探测评价裂缝的示踪剂特性研究

针对裂缝热中子示踪探测方法,从中子双组扩散理论入手结合蒙特卡洛数值模拟方法,分析压裂前后地层热中子分布影响因素,并模拟不同类型示踪剂及含量的热中子裂缝响应规律,筛选最佳示踪剂并给出其在支撑剂中含量的上、下限。结果表明:压裂前后热中子计数变化量主要受裂缝宽度和标记支撑剂中示踪剂含量的影响;钆对裂缝宽度变化反应最灵敏,钆元素是作为标记支撑剂的最佳示踪元素;随支撑剂中Gd 2O 3含量的增加,热中子计数率降低,热中子计数变化量D增加;示踪剂中氧化钆的上、下限值随裂缝宽度呈指数降低,且当裂缝宽度为1.0 cm时,Gd 2O 3的质量分数上限为0.68%,下限为0.03%。     

具有Logistic增长项的两种群竞争Keller-Segel模型的稳定性分析

应用线性化方法研究两种群竞争的Keller-Segel模型常数平衡解的个数及其稳定性问题.     

A Forward Selection Method on Customer Credit

In this paper, we discuss a selection and evaluation method of customer credit for the commercial bank loans operation, and put forth a forward selection model by optimization techniques. At last, we also give an example to analyze its application.     

Empirical Test for Earnings Management of Top Managers＇ Change in Listed Companies

Top managers play a significant role on business decision in listed companies. The frequency of top managers＇ change is rather high all along. Whether those listed companies which top managers changed can really improve performances？ In this paper, we will discuss whether listed companies improve the financial index through earning management and give some advice on top managers＇ change in listed companies in China.     

浅谈饭店"环境入世"

环境恶化，生态平衡破坏，使对可持续发展的研究愈来愈重要．通过对饭店经营观念的转变。创建绿色饭店环境成本和效益的分析，提出实现饭店可持续发展的途径．     

THE INDUSTRIAL UTILIZATION OF CHEMICAL MODIFIED AGRICULTURAL RESIDUES

INTRODUCTIONToday, the world's industry is utilizing less than 10% of biomass of raw materials from plantation [1]. Agricultural residues, such as cereal straws are important and abundant renewable organic resources of energy and production of a diversity of chemicals, including ethanol production [2], activated carbon [3] and ion exchangers [4]. Many other applications for Cereal straws are in the process of being developed.In china, wheat, maize and sorghum are the three major crops, w…     

关于信息技术与教学整合的探讨

本文讨论了信息技术与教学整合的基本概念、作用和意义。并分析了影响信息技术与教学整合的主要因素．     

碳钢膏剂无孔渗硅工艺的研究

本研究用膏剂法进行无孔渗硅研究,透射电镜、电子探针和M351腐蚀仪分析证实:获得了致密、无孔隙、具有良好耐磨性和耐腐蚀性的渗硅层,并分析了渗硅层形成机理及表层疏松层以及内部孔隙成因。     

粉末冶金陶瓷模工艺中的快速脱蜡新技术

粉末冶金陶瓷模工艺是一种先进的过净形成形工艺．本文报道该工艺中一种新的脱蜡技术．采用快速加热、管径集中热量和定向导热传热综合方法，在陶瓷模和大部分蜡模材料处于较低温度下，使蜡模材料来不及发生显著的热膨胀而直接蒸发，得到脱蜡干净、外形完整的陶瓷模．     

林肯羊与陕北地方绵羊杂交后代产肉性能研究

林肯羊和陕北地方土种绵羊杂交后代,不但能提高当地绵羊的产毛量和羊毛品质,而且能显著地提高产肉量和肉品质,经济效益十分显著。